I consider this so low priority to not be worth looking at, but I “believe” I’ve seen it happen enough that it may help clear up other support questions, so I’m writing it up.

On the AI turn, when an explosion ability, for example Gorgothra/Herdmaster cause the first unit to be killed while a new turn is generated. This seems to allow the next damage ability to target the dead unit. I believe this is one of the causes of the AI defense with Orion/Barbearus to fire into nothing.

What you were expecting to happen, and what actually happened?
The AI exploded with Herdmaster, killing my first unit in line with exploding skulls.
Cascade filled the AI Herdmaster again, while generating a new turn.
Herdmaster cast explosion again, exploding 6 skulls. The 6 damage attempted to apply to the dead unit. I would have expected this to hit the next unit in line, as it was an ability fired after the cascade had resolved.

What are the steps to make it happen again?
On defense, have an exploding gem unit kill the first unit in line, while generating a cascade creating a new turn. Then have the AI choose to randomly target the killed unit, or explode and see damage attempt to apply to the dead unit, without making any move before triggering the ability.

Do you have any screenshots or video you want to share with us so we can see the problem? Attach them to your post!
I don’t have any screenshots.